#! /bin/sh
#
# mhmail.c -- simple mail program
#
# This code is Copyright (c) 2012, by the authors of nmh.  See the
# COPYRIGHT file in the root directory of the nmh distribution for
# complete copyright information.
#
# Emulation of compiled mhmail(1) using nmh post(8) or send(1).
# Differences from compiled mhmail:
# * Supports all post(8) (by default, without -profile) or send(1)
#   (with -profile) options.
# * Optionally (with -profile) obeys the users profile, including
#   AliasFile and send entries.
# * Adds -debug option for debugging (sending, not incorporating new mail).
#
# To do:
# * set prefix properly so that it supports distcheck
# * support undocumented mhmail options?

usage='Usage: mhmail [addrs ... [switches]]
  switches are:
  -b(ody) text
  -c(c) addrs ...
  -f(rom) addr
  -s(ubject) text
  -pr(ofile)
  -v(ersion)
  -h(elp)
  -d(ebug)
  and all post(8)/send(1) switches'

#### Use autoconf to fill in bindir.
# This doesn't work with distcheck.
# prefix=@prefix@
# exec_prefix=@exec_prefix@
# nmhbindir=@bindir@
nmhbindir=`dirname $0`

#### Or if configure/make haven't been run yet, figure out nmhbindir at runtime.
case ${nmhbindir} in
  @*@) nmhbindir=`dirname $0` ;;
esac

if [ $# -eq 0 ]; then
  #### Emulate mhmail for reading mail.
  exec ${nmhbindir}/inc
else
  #### Go through all the switches so we can build the draft.
  tolist=
  body=
  bodyarg=0
  cclist=
  ccarg=0
  havefrom=0
  header=
  otherarg=0
  postsendargs=
  switcharg=0
  use_send=0
  debug=
  for arg in "$@"; do
    case ${arg} in
      -*) switcharg=0
    esac

    case ${arg} in
      #### Post and send won't accept -f -or -s because they'd be
      #### ambiguous, so no conflicts with them.  And they don't have
      #### -b or -c.  For the new switches that compiled mhmail didn't
      #### have:  let -p indicate mhmail -profile, not send -port, and
      #### let -d indicate mhmail -debug, not send -draft.
      -b|-bo|-bod|-body) bodyarg=1 ;;
      -c|-cc) ccarg=1 ;;
      -d|-de|-deb|-debu|-debug) debug=echo ;;
      -f|-fr|-fro|-from) header="${header}From:"; otherarg=1; havefrom=1 ;;
      -h|-he|-hel|-help) printf "%s\n" "${usage}"; exit ;;
      -p|-pr|-pro|-prof|-profi|-profil|-profile) use_send=1 ;;
      -s|-su|-sub|-subj|-subje|-subjec|-subject)
          header="${header}Subject:"; otherarg=1 ;;
      -v|-ve|-ver|-vers|-versi|-versio|-version)
          #### Cheat instead of using autoconf and make to fill in the version.
          ${nmhbindir}/mhpath -v | sed 's/mhpath/mhmail/'; exit ;;
      -*) postsendargs="${postsendargs:+${postsendargs} }${arg}"; switcharg=1 ;;
      *) if [ ${ccarg} -eq 1 ]; then
           cclist="${cclist:+${cclist}, }${arg}"; ccarg=0
         elif [ ${bodyarg} -eq 1 ]; then
           body="${arg}
"; bodyarg=0
           #### Allow -body "" by using just a newline for the body.
           [ "${body}"x = x ]  &&  body='
'
         elif [ ${otherarg} -eq 1 ]; then
           #### Always end ${header} with a newline.
           header="${header:+${header} }${arg}
"; otherarg=0
         elif [ ${switcharg} -eq 1 ]; then
           postsendargs="${postsendargs:+${postsendargs} }${arg}"
         else
           #### An address.
           tolist="${tolist:+${tolist}, }${arg}"
         fi
    esac
  done

  #### Check for at least one address and -from.
  if [ "${tolist}"x = x ]; then
    printf "mhmail: usage: mhmail addrs ... [switches]\n"; exit 1
  fi
  if [ "${havefrom}" = 0 ]; then
    nmhlibdir=`${nmhbindir}/mhparam libdir`
    header="${header:+${header}}From: "\
`${nmhlibdir}/ap -format '%(localmbox)' 0`'
'
  fi

  #### If no -body, read message from stdin the easy way.
  if [ "${body}"x = x ]; then
    #### This will lose any trailing newline(s), so we can't
    #### send the message when stdin contains only newlines.
    body=`cat`

    #### Don't allow an empty body (from stdin).
    if [ "${body}"x = x ]; then
      printf "empty body, message not sent\n"
      exit 1
    fi

    #### Add trailing newline to body if it doesn't have one.
    [ `printf "${body}" | tail -n 1 | wc -l` -ne 1 ]  &&  body="${body}
"
  fi

  #### Set up a tmpfil and trap to remove it.  send moves the file to a backup.
  tmpdir="${MHTMPDIR:-${TMPDIR:-${TMP:-`${nmhbindir}/mhpath +`}}}"
  tmpfil="${tmpdir}/mhmail$$"
  tmpfilbackup="${tmpdir}/[,#]mhmail$$"
  trap "rm -f ${tmpfil} ${tmpfilbackup}" EXIT

  #### Put message header and body in file to supply as draft to
  #### send/post.  ${header} always ends with a newline, so this adds
  #### the blank that separates the body.
  umask 077
  printf "%s" "To: ${tolist}
Cc: ${cclist}
${header}
${body}" > ${tmpfil} || exit 1

  if [ "${debug}" ]; then
    printf "%s:\n" `ls -1 ${tmpfil}`
    cat "${tmpfil}"
  fi

  if [ "$use_send" -eq 0 ]; then
    post_or_send="${nmhlibdir:=`${nmhbindir}/mhparam libdir`}/post"
  else
    post_or_send="${nmhbindir}/send"
  fi

  if $debug ${post_or_send} ${tmpfil} ${postsendargs}; then
    :
  else
    printf "Letter saved in dead.letter\n"
    #### exec skips the trap set above.
    exec mv ${tmpfil} dead.letter
  fi
fi